Cache optimization

ABSTRACT

A system and method for management and processing of resource requests at cache server computing devices is provided. Cache server computing devices segment content into an initialization fragment for storage in memory and one or more remaining fragments for storage in a media having higher latency than the memory. Upon receipt of a request for the content, a cache server computing device transmits the initialization fragment from the memory, retrieves the one or more remaining fragments, and transmits the one or more remaining fragments without retaining the one or more remaining fragments in the memory for subsequent processing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/060,015, entitled CACHE OPTIMIZATION, and filed Mar. 31, 2008, thedisclosure of which is incorporated herein by reference.

BACKGROUND

Generally described, computing devices and communication networks can beutilized to exchange information. In a common application, a computingdevice can request content from another computing device via thecommunication network. For example, a user at a personal computingdevice can utilize a software browser application to request a Web pagefrom a server computing device via the Internet. In such embodiments,the user computing device can be referred to as a client computingdevice and the server computing device can be referred to as a contentprovider.

Content providers are generally motivated to provide requested contentto client computing devices often with consideration of efficienttransmission of the requested content to the client computing deviceand/or consideration of a cost associated with the transmission of thecontent. For larger scale implementations, a content provider mayreceive content requests from a high volume of client computing deviceswhich can place a strain on the content provider's computing resources.Additionally, the content requested by the client computing devices mayhave a number of components, which can further place additional strainon the content provider's computing resources.

With reference to an illustrative example, a requested Web page, ororiginal content, may be associated with a number of additionalresources, such as images or videos, that are to be displayed with theWeb page. In one specific embodiment, the additional resources of theWeb page are identified by a number of embedded resource identifiers,such as uniform resource locators (“URLs”). In turn, software on theclient computing devices typically processes embedded resourceidentifiers to generate requests for the content. Often, the resourceidentifiers associated with the embedded resources reference a computingdevice associated with the content provider such that the clientcomputing device would transmit the request for the additional resourcesto the referenced content provider computing device. Accordingly, inorder to satisfy a content request, the content provider would provideclient computing devices data associated with the Web page as well asthe data associated with the embedded resources.

Some content providers attempt to facilitate the delivery of requestedcontent, such as Web pages and/or resources identified in Web pages,through the utilization of a content delivery network (“CDN”) serviceprovider. A CDN server provider typically maintains a number ofcomputing devices in a communication network that can maintain contentfrom various content providers. In turn, content providers can instruct,or otherwise suggest to, client computing devices to request some, orall, of the content provider's content from the CDN service provider'scomputing devices.

As with content providers, CDN service providers are also generallymotivated to provide requested content to client computing devices oftenwith consideration of efficient transmission of the requested content tothe client computing device and/or consideration of a cost associatedwith the transmission of the content. Accordingly, CDN service providersoften consider factors such as latency of delivery of requested contentin order to meet service level agreements or to generally improve thequality of delivery service.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram illustrative of one embodiment of a contentdelivery network (CDN) based system including one or more cache servers;

FIG. 2 is a block diagram of the CDN-based system of FIG. 1 illustratingthe processing of a content request by a content provider;

FIG. 3 is a block diagram of the CDN-based system of FIG. 1 illustratingthe processing of a DNS query and assignment of a resource cachecomponent;

FIGS. 4A-4F are simplified block diagrams of the CDN-based system ofFIG. 1 illustrating embodiments associated with the processing of theresource request by a cache server;

FIG. 5 is a flow diagram of an illustrative method for processing aresource request at a cache server; and

FIG. 6 is a flow diagram of an illustrative method for managing storageof a resource at a cache server.

DETAILED DESCRIPTION

Generally described, the present disclosure is directed to themanagement of cache resources utilized when a client computing devicerequests content from a network resource, such as content deliverynetwork (“CDN”) service providers. Specifically, aspects of thedisclosure will be described with regard to the processing, by aresource cache component, of content, and segmentation of the contentwith respect to both the storage and retrieval thereof. Although variousaspects of the disclosure will be described with regard to illustrativeexamples and embodiments, one skilled in the art will appreciate thatthe disclosed embodiments and examples should not be construed aslimiting.

FIG. 1 is a block diagram illustrative of a content delivery environment100 for the management of content storage and delivery. As illustratedin FIG. 1, the content delivery environment 100 includes a number ofclient computing devices 102 (generally referred to as clients) forrequesting content from a content provider and/or a CDN serviceprovider. In an illustrative embodiment, the client computing devices102 can correspond to a wide variety of computing devices includingpersonal computing devices, laptop computing devices, hand-heldcomputing devices, terminal computing devices, mobile devices, wirelessdevices, various electronic devices and appliances and the like. In anillustrative embodiment, the client computing devices 102 includenecessary hardware and software components for establishingcommunications over a communication network 108, such as a wide areanetwork or local area network. For example, the client computing devices102 may be equipped with networking equipment and browser softwareapplications that facilitate communications via the Internet or anintranet.

Additionally, the client computing devices 102 may also includenecessary hardware and software components to execute, or otherwiseprocess, translation information as will be described in greater detailbelow. One skilled in the relevant art will appreciate that additionalhardware/software components for processing the translation informationmay be included with the execution of a multi-purpose softwareapplication, such as a browser software application. Alternatively, someor all of the additional hardware/software components may be embodied instand alone or specialized components configured for processing thetranslation information. Although not illustrated in FIG. 1, each clientcomputing device 102 utilizes some type of local DNS resolver component,such as a DNS Name server, that generates the DNS queries attributed tothe client computer. In one embodiment, the local DNS resolver componentmay belong to an enterprise network to which the client computerbelongs. In another embodiment, the local DNS resolver component maybelong to an Internet Service Provider (ISP) that provides the networkconnection to the client computer.

The content delivery environment 100 can also include a content provider104 in communication with the one or more client computing devices 102via the communication network 108. The content provider 104 illustratedin FIG. 1 corresponds to a logical association of one or more computingdevices associated with a content provider. Specifically, the contentprovider 104 can include a web server component 110 corresponding to oneor more server computing devices for obtaining and processing requestsfor content (such as Web pages) from the client computing devices 102.The content provider 104 can further include an origin server component112 and associated storage component 114 corresponding to one or morecomputing devices for obtaining and processing requests for networkresources from the CDN service provider. One skilled in the relevant artwill appreciate that the content provider 104 can be associated withvarious additional computing resources, such additional computingdevices for administration of content and resources, DNS name servers,and the like.

With continued reference to FIG. 1, the content delivery environment 100can further include a CDN service provider 106 in communication with theone or more client computing devices 102 and the content providers 104via the communication network 108. The CDN service provider 106illustrated in FIG. 1 corresponds to a logical association of one ormore computing devices associated with a CDN service provider.Specifically, the CDN service provider 106 can include a number of Pointof Presence (POP) locations 116, 122 that correspond to nodes on thecommunication network 108. Each POP 116, 122 includes a DNS component118, 124 made up of a number of DNS server computing devices forresolving DNS queries from the client computers 102.

Each POP 116, 122 also includes a resource cache component 120, 126 forstoring objects from content providers and transmitting variousrequested objects to various client computers. Each resource cachecomponent 120, 126 is made up of a number of cache server computingdevices 130, 132, 134 for obtaining and processing requests for networkresources. Each cache server computing device 130, 132, 134 includes amemory 140, 142, 144 having the lowest data access latency, generallyreferred to as latency, for the corresponding cache server computingdevice. One skilled in the relevant art will appreciate that forpurposes of the present disclosure data access latency can include,among other things, a minimal time period in which stored data can beretrieved from a memory location and available for transmission. Inaddition, each cache server computing device 130, 132, 134 can beassociated with, either directly or shared via a bus or otherwise, astorage media 150, 152, 154 having a higher latency than the attachedmemory 140, 142, 144. Storage media 150, 152, 154 can include, forexample, non-volatile memory such as a disk memory, flash memory,optical memory, and the like. Even further, the content deliveryenvironment 100 can include a network-based memory 160 which can beutilized by cache server computing devices 130, 132, 134, as well as byother computing devices, for the management of content. Similar tostorage media 150, 152, 154, the network-based memory 160 is associatedwith a higher latency than the attached memory 140, 142, 144.

In an illustrative embodiment, the DNS component 118, 124 and resourcecache component 120, 126 are considered to be logically grouped,regardless of whether the components, or portions of the components, arephysically separate. Additionally, although the POPs 116, 122 areillustrated in FIG. 1 as logically associated with the CDN serviceprovider 106, the POPs will be geographically distributed throughout thecommunication network 108 in a manner to best serve various demographicsof client computing devices 102. Additionally, one skilled in therelevant art will appreciate that the CDN service provider 106 can beassociated with various additional computing resources, such additionalcomputing devices for administration of content and resources, and thelike.

One skilled in the relevant art will appreciate that the components andconfigurations provided in FIG. 1 are illustrative in nature.Accordingly, additional or alternative components and/or configurations,especially regarding the additional components, systems and subsystemsfor facilitating communications may be utilized.

With reference now to FIGS. 2-4, the interaction between variouscomponents of the content delivery environment 100 of FIG. 1 will beillustrated. For purposes of the examples, however, the illustrationshave been simplified such that many of the components utilized tofacilitate communications are not shown. One skilled in the relevant artwill appreciate that such components can be utilized and that additionalinteractions would accordingly occur without departing from the spiritand scope of the present disclosure. Additionally, althoughcommunications may be illustrated as direct communications betweencomponents, one skilled in the relevant art will appreciate that all theillustrative communications may occur directly between components orfacilitated via the communication network 108. Prior to discussing themanagement of objects by the cache server computing devices 140, 142,144, a brief overview of the general processing of resource requestsfrom a client computing device 102 in a CDN-based system will bedescribed.

With reference to FIG. 2, a client computing device 102 generates acontent request that is received and processed by the content provider104, such as through the Web server 110. In accordance with anillustrative embodiment, the request for content can be in accordancewith common network protocols, such as the hypertext transfer protocol(“HTTP”). Upon receipt of the content request, the content provider 104identifies the appropriate responsive content. In an illustrativeembodiment, the requested content can correspond to a Web page that isdisplayed on the client computing device 102 via the processing ofinformation, such as hypertext markup language (“HTML”), extensiblemarkup language (“XML”), and the like. The requested content can alsoinclude a number of embedded resource identifiers, described above, thatcorresponds to resource objects that should be obtained by the clientcomputing device 102 as part of the processing of the requested content.The embedded resource identifiers can be generally referred to asoriginal resource identifiers or original URLs.

In one embodiment, the original URLs identify the domain of the CDNservice provider 106 (e.g., “cdnprovider.com”), the same name of theresource to be requested (e.g., “resource.xxx”) and the same path wherethe resource will be found (e.g., “path”). Additionally, the originalURL can include additional processing information (e.g., “additionalinformation”). The original URL would have the form of:

-   -   http://additional_information.cdnprovider.com/path/resources.xxx

In another embodiment, the information associated with the CDN serviceprovider 106 is included the original URL, such as through prepending orother techniques, such that the original URL can maintain all of theinformation associated with a URL previously associated with the contentprovider 104. In this embodiment, the original URL would have the formof:

-   -   http://additional_information.cdnprovider.com/www.contentprovider.com/path/resource.xxx

Upon receipt of the requested content, the client computing device 102,such as through a browser software application, begins processing any ofthe markup code included in the content and attempts to acquire theresources identified by the embedded resource identifiers. Accordingly,the first step in acquiring the content correspond to the issuance, bythe client computing device 102 (through its local DNS resolver), a DNSquery for the Original URL resource identifier that results in theidentification of a DNS server authoritative to the “.” and the “com”portions of the translated URL. After resolving the “.” and “com”portions of the embedded URL, the client computing device 102 thenissues a DNS query for the resource URL that results in theidentification of a DNS server authoritative to the “.cdnprovider”portion of the embedded URL. The issuance of DNS queries correspondingto the “.” and the “com” portions of a URL are well known and have notbeen illustrated.

With reference now to FIG. 3, in an illustrative embodiment, thesuccessful resolution of the “cdnprovider” portion of the original URLidentifies a network address, such as an IP address, of a DNS servercomponent 118 associated with the CDN service provider 106. In oneembodiment, the IP address is a specific network address unique to a DNSserver component 118 of POP 116. In another embodiment, the IP addresscan be shared by one or more POPs 116, 122. In this embodiment, a DNSquery to the shared IP address utilizes a one-to-many network routingschema, such as anycast, such a specific POP, POP 118, will receive therequest as a function of network topology. For example, in an anycastimplementation, a DNS query issued by a client computing device 102 to ashared IP address will arrive at a DNS server component logically havingthe shortest network topology distance, often referred to as networkhops, from the client computing device. The network topology distancedoes not necessarily correspond to geographic distance. However, in someembodiments, the network topology distance can be inferred to be theshortest network distance between a client computing device 102 and aPOP.

With continued reference to FIG. 3, in either of the above identifiedembodiments (or any other embodiment), a specific DNS server in the DNScomponent 118 of a POP 116 receives the DNS query corresponding to theoriginal URL from the client computing device 102. Once one of the DNSservers in the DNS component 118 receives the request, the specific DNSserver attempts to resolve the request. In an illustrative embodiment, aspecific DNS server can resolve the DNS query by identifying an IPaddress of a cache server component that will process the request forthe requested resource. As described above, a selected resource cachecomponent 120, 126 can process the request by either providing therequested resource if it is available or attempt to obtain the requestedresource from another source, such as a peer cache server computingdevice or the origin server 112 of the content provider 104.

Upon selection of a cache server computing device 140, 142, 144 (or aresource cache component 120, 126), the DNS server component 118provides an IP address of the cache server computing device, resourcecache component or load balancer/load share device associated with aresource cache component. The client computing device 102 can thenutilize Internet communication protocols to request the resource from acache server computing device 140, 142, 144 identified by the IPaddress. The cache server computing device 140, 142, 144 then processesthe request, as will be described in greater detail below, to providethe resource to the client computing device 102. Specifically, the cacheserver computing device can begin transmitting an initialization portionof the requested content from a local memory while receiving theremaining portions of the requested the content from other storagelocations. Upon receipt, the requested resource is then processed by thebrowser application on the client computing device 102 as appropriate.

Referring now to FIGS. 4A-4F, multiple embodiments of the interactionbetween various components of the content delivery environment 100 willbe described with respect to the processing of a resource request by acache server computing device 140, 142, 144. For purposes of theexamples in FIGS. 4A-4F, however, the illustrations have been simplifiedsuch that many of the systems, subsystems, and components utilized tofacilitate communications are not shown. In general, and as will bedescribed in greater detail below, objects stored in cache servercomputing devices 130, 132, 134 are each segmented into aninitialization fragment for storage in memory 140, 142, 144 and one ormore remaining fragments for storage in a media having a higher latencythan the memory in which the initialization fragment is stored. In oneembodiment, the one or more remaining fragments comprise a majorityfragment.

With reference now to FIG. 4A, a cache server computing device 132receives a request for an object from a client computing device 102.Upon receipt of the request for the object, the cache server computingdevice 132 begins retrieving a majority fragment of the object from astorage media associated with the cache server computing device, such asa local disk memory 152 in this example. In one example, the storagelocation of the majority may be previously known to the cache servercomputing device 132 such that the request for the majority fragmentportion may be sent immediately. Alternatively, in another example, thecache server computing device 132 may query a directory or a service toidentify an appropriate storage location for the majority fragmentportion. The service may be utilized to identify a best or availablestorage locations if the majority fragment portion is stored in multiplestorage locations (such as for purposes of geographic distribution).

Substantially at the same time as the request for the majority fragmentportion, the cache server computing device 132 begins transmitting theinitialization fragment over a network to the requesting clientcomputing device 102 from a memory component 142. In this embodiment,the local disk memory 152 likely has a higher latency associated withrecall of data therefrom than the memory 142 (e.g. RAM) of the cacheserver computing device 132. Accordingly, retrieving the initializationfragment from the memory 132 allows the cache server computing device tobegin transmitting at least a portion of the requested object as soon asthe request is processed. At the same time, the size of theinitialization fragment is sufficiently large such that the majorityfragment, or fragments, can be retrieved prior to completion of thetransmission of the initialization fragment portion. The cache servercomputing device 132 can then begin transmitting the majority fragmentover the communication network to the requesting client computing device102 upon completion of the transmission of the initialization fragmentportion from memory 142. Alternatively, the cache server computingdevice 132 can then begin transmitting the majority fragment over thecommunication network to the requesting client computing device 102 assoon as it begins receiving the majority fragment. Although theinitialization fragment portion is shown as being provided from thelocal cache server computing device memory 142, one skilled in therelevant art will appreciate that the initialization fragment portionmay be stored and transmitted from other storage locations and/or byother cache server computing devices.

In one embodiment, the majority fragment portion is not retained by thecache server computing device 132 for processing a subsequent requestfor the same object. One skilled in the relevant art will appreciatethat in accordance with the operation of a cache server computingdevice, such as cache server computing device 132, the majority fragmentportion may be stored in memory 142 in order to be transmitted to theclient computing device 102. In this embodiment, however, such storagewould be considered to be generally transient as the majority fragmentportion may be deleted (or at least prioritized for overwriting).

It will be appreciated by one skilled in the relevant art that theprecise timing of locating, retrieving and transmitting theinitialization and majority fragments can vary. It will also beappreciated by one skilled in the relevant art that as a networkincludes a number of local and non-local storage media, the majorityfragments can be stored on any storage media within a POP 116, 122 or inthe network 108 having a higher latency than the memory on which theinitialization fragment is stored. For example, one or more majorityfragments may be stored in the local disks of peer cache servercomputing devices of a POP, on a network-based storage 160, on thecontent provider's origin server 112, and the like. As described above,when an object is requested by a client computing device 102, thereceiving cache server computing device can begin providing theinitialization fragment immediately from a local memory, while themajority fragment segment is retrieved from another location such as acache peer's disk.

In another illustrative embodiment, the requested object can besegmented into three or more fragments for retrieval. In thisembodiment, the initialization fragment can be stored in memory of acache server computing device in a manner as previously described.Additionally, an intermediate fragment is stored on another storagelocation, such as a cache server computing device disk, while themajority fragment is stored on yet another storage location, such as onthe origin server 112. When the initialization fragment begins to beserved, the intermediate fragment is retrieved and served, and themajority fragment is retrieved from the origin server. In oneembodiment, the storage location of the intermediate fragment may have ahigher latency than the memory (e.g., storage location of theinitialization fragment portion) but a lower latency than the storagelocation of the majority fragment portion. Accordingly, the size of theintermediate fragment portion would be a function to the time requiredto retrieve the majority fragment portion. Alternatively, the latency ofthe storage locations of the intermediate and majority fragment portionsmay not be substantially different. In this embodiment, the intermediateand majority fragment portions may be allocated according to financialor service criteria, such as cost of storage, cost of bandwidth,guaranteed service availability, redundant storage, and the like. Asalso described above with regard to FIG. 4A, in one embodiment, theinitialization and majority fragment portions would not be retained bythe cache server computing device for processing a subsequent requestfor the same object.

With reference now to FIGS. 4B-4D, the processing performed by thevarious components in these illustrative embodiments is similar to thatdescribed in reference to FIG. 4A with the exception that the storagelocation from which the majority fragment is provided. With reference toFIG. 4B, the cache server computing device 132 obtains the request foran object and then begins retrieving the majority fragment of therequested object from disk memory 150 of another cache server computingdevice 130. In this example, the cache server computing device 130 is inthe same POP 116. In the same manner described above, the receivingcache server computing device 132 then transmits the initializationfragment portion and the majority fragment portion to the clientcomputing device 102. As previously described, the majority fragmentportion may be stored in memory 142 to facilitate the transmission tothe client computing device 102. The majority fragment portion may notbe maintained in the memory 142 however for subsequent requests for theobject.

With reference now to FIG. 4C, the cache server computing device 132again receives the request for an object from the client computingdevice 102. In this illustrative example, however, the cache servercomputing device 132 requests the majority fragment from disk memory 150of another cache server computing device 130 from a different POP 122.The cache server computing device 132 would then begin transmitting theinitialization fragment portion while retrieving the majority fragmentportion. Subsequently, the majority fragment portion would betransmitted. In yet another alternative embodiment, the majorityfragment may be retrieved from a separate network-based memory 160 asshown in FIG. 4D, or from a storage media 114 associated with the originserver component 112 as shown in FIG. 4E. In both of these embodiments,the size of the initialization fragment portion may be larger than thesize of the initialization fragment portion discussed with regard to theexamples in FIGS. 4B-4D in the event of additional latencies associatedwith the network communications. As will be described below, the size ofthe initialization fragment portion may be dynamically adjusted.

Turning now to FIG. 4F, in yet a further embodiment, the requestedobject transmitted by the cache server computing device 132 can besegmented into an initialization fragment, an intermediate fragment, anda majority fragment. In particular, upon request of the object, thecache server computing device 132 retrieves the intermediate fragmentassociated with the object from a first storage media, such as hard disk152. As previously described, the hard disk 152 has a higher latencythan the memory 142 of the cache server computing device 132. At thesame time, the cache server computing device 140, 142, 144 beginsretrieving the majority fragment associated with the object from asecond storage media, also having higher latency than the memory 142 ofthe cache server computing device 132. In this embodiment, the secondstorage media is a storage media associated with the origin servercomponent 112. Substantially at the same time, the cache servercomputing device 132 begins transmitting the initialization fragment ofthe object from memory 142 over the network to the requesting clientcomputing device 102. As soon as the intermediate fragment is retrieved,the cache server computing device starts transmitting the intermediatefragment over the network to the requesting client computing device, andlikewise for the majority fragment. Again, it will be appreciated by oneskilled in the relevant art that the precise timing of locating,retrieving and transmitting the initialization, intermediate, andmajority fragments can vary. Additionally, as previously described,although the intermediary and majority fragment portions may be storedin memory 142 to facilitate the transmission to the client computingdevice 102, these portions may not be maintained in the memory 142however for subsequent requests for the object.

With reference now to FIG. 5, one embodiment of a routine 500 forprocessing a resource request at a cache server computing device 130,132, 134 will be described. At block 502, the routine 500 begins withthe receipt of a request for an object at the cache server computingdevice 130, 132, 134. As previously described, a specific IP address ofa cache server may be assigned by a DNS server associated with the CDNservice provider 106. Alternatively, a specific cache server computingdevice 130, 132, 134 may be selected by software/hardware components ata resource cache component.

At block 504, the cache server computing device 130, 132, 134 finds andbegins transmission of an initialization fragment for the object frommemory 140, 142, 144 of the cache server computing device. In anillustrative embodiment, the memory 140, 142, 144 corresponds to a localmemory associated with the receiving cache server computing device.Alternatively, the memory may correspond to a memory of a peer cacheserver computing device, such as within the same POP or across POPs.Still further, although the initialization fragment portion has alwaysbeen illustrated as stored on a memory, one skilled in the relevant artwill appreciate that the initialization fragment portion may also beprovided from other storage locations. Such variations are considered tobe within the scope and spirit of the present disclosure.

At block 506, the cache server computing device begins retrieving allremaining portions of the object, including all intermediary andmajority fragments. In an illustrative embodiment, the intermediary andmajority fragment portion are stored on a media having a higher latencythan the memory. As previously described, the cache server computingdevice can utilize a service or transmit a request in the event that thestorage location for the majority fragment portion is not known or ifmultiple storage locations exist. At decision block 508, a test isconducted to determine whether the transmission of the initializationfragment portion is complete. If the transmission is not complete, thecache server computing device continues to transmit the initializationfragment portion from memory. Additionally, if the majority fragmentportion is not downloaded, the cache server computing device continuesto download the majority fragment portion (or intermediate fragmentportions).

Upon completion of the transmission of the initialization fragmentportions, at block 510, the cache server computing device then beginstransmission of the remaining fragment portions (including allintermediary and majority fragments) over the network to the requestingclient computing device 102. At block 514, the cache server computingdevice can then delete any intermediary or majority fragment portionsthat were stored in memory as part of the transmission process. In anillustrative embodiment, the cache server computing device mayexplicitly delete the intermediary or majority fragment portions frommemory. In another embodiment, the cache server computing device maymark the memory used to store the intermediary or majority fragmentportions as available for overwriting. In still a further embodiment,the cache server computing device may lower the priority in a memorymanagement algorithm for the memory used to store the intermediary ormajority fragment portions. Additionally, block 514 may be optionallyomitted. The routine ends at block 516.

In other embodiments, the commencement of transmission of theinitialization fragment occurs immediately upon receipt of the requestfor the associated object, with the request for retrieval of themajority fragment occurring simultaneously with or immediatelysubsequent to the commencement of transmission of the initializationfragment.

With reference now to FIG. 6, one embodiment of a routine 600 formanaging storage of a resource at a cache server computing device willbe described. At block 602, the cache server computing device receives arequest for storage of an object. At block 604, the cache servercomputing device determines an initialization fragment and one or moreremaining fragments associated with the object. Part of the process ofmaking such determination includes determining the size of theinitialization fragment. In one embodiment, the size of theinitialization fragment is based on the latency associated withretrieving the one or more remaining fragments from other storagelocation as compared to the latency associated with transmitting (at thesame time) the initialization fragment portion. As previously described,the size of the initialization chunk can be selected such that theretrieval of the intermediary and/or majority fragment portions iscomplete prior to completion of the transmission of the initializationfragment portion to the client computing device 102. Specifically, thesize of the initialization fragment can be based on the throughput ofthe number of network packets that can be sent during the average ormaximum latency of the storage media as compared to the fastest possiblethroughput of packets to a client computing device 102. It will beappreciated by one skilled in the relevant art that the size of theinitialization fragment can be determined in a number of ways, such asstatically or dynamically or otherwise, and based on a variety offactors, including those described above, as well as others such as theencoding rate of the object.

In another embodiment, additional cache management methodologies may beintegrated into the consideration size of the initialization fragmentportion. In one example, the size of the initialization fragment can bebased on a frequency of a request for the object. For example, an objectthat is frequently requested could have a larger initialization fragmentsize so as to reduce the number of I/O requests required to serve theone or more remaining fragments from the higher latency storage media.In another example, the size of the initialization fragment is based ona frequency of a request for another object related to the requestedobject.

With reference again to FIG. 6, at block 606, the cache server computingdevice then stores the initialization fragment in memory of the cacheserver computing device. Alternatively, the cache server computingdevice may simply associate the initialization fragment with a storagelocation and store the association, especially for example where anothercomputing device controls the storage of the initialization fragment. Atblock 608, the cache server computing device stores the one or moreremaining fragments in one or more storage locations. Again,alternatively, the cache server computing device may simply associatethe one or more remaining fragments with the selected one or morestorage locations and store the association.

In another illustrative embodiment, the size of the majority fragment isthe whole file size of the object. In accordance with this embodiment,the cache server component can receive the entire object as theintermediary and/or majority fragment portion and filter the fragmentsthat have not yet been transmitted. Alternatively, the cache servercomputing device may request only portions of the majority file from itsstorage location. However, by storing the entire object as the majorityand/or intermediary fragments, the size of the initialization fragmentportion may be dynamically modified without requiring a correspondingmodification to the other fragment portions. Alternatively, in anotherembodiment, the size of the intermediate and majority fragments eachcorrespond such that all the fragments sum up to the whole file size ofthe object.

At decision block 610, the cache server computing device determineswhether the initialization fragment needs to be updated. There are anumber of ways in which such determination may be made. In a fewillustrative examples, the decision block 610 can be based on adetermination of a latency associated with retrieval of the majorityfragment, a frequency of a request for the object, and/or a frequency ofa request for another object related to the requested object. In oneembodiment, the decision block 610 includes a specific determination asto a new file size for the initialization fragment. The new file sizecan be determined in similar ways and based on similar factors presentedabove for determining the initial file size of the initializationfragment.

At block 612, if a determination is made that an update is needed, thecache server computing device stores an incremental fragment in thememory of the cache server computing device to supplement theinitialization fragment. In one embodiment, the size of the incrementalfragment and the original initialization fragment together correspond tothe newly determined file size for the initialization fragment.Alternatively, in another embodiment, if an update is needed, a newinitialization fragment of the appropriate size, which is determinedthrough the update process, replaces the original initializationfragment in the memory. The routine ends at block 614. One skilled inthe relevant art will appreciate that portions of routine 600 (such asblocks 610 and 612) may be continuously implemented to update thefragment portions.

It will be appreciated by those skilled in the art and others that allof the functions described in this disclosure may be embodied insoftware executed by one or more processors of the disclosed componentsand mobile communication devices. The software may be persistentlystored in any type of non-volatile storage.

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

Any process descriptions, elements, or blocks in the flow diagramsdescribed herein and/or depicted in the attached figures should beunderstood as potentially representing modules, segments, or portions ofcode which include one or more executable instructions for implementingspecific logical functions or steps in the process. Alternateimplementations are included within the scope of the embodimentsdescribed herein in which elements or functions may be deleted, executedout of order from that shown or discussed, including substantiallyconcurrently or in reverse order, depending on the functionalityinvolved, as would be understood by those skilled in the art. It willfurther be appreciated that the data and/or components described abovemay be stored on a computer-readable medium and loaded into memory ofthe computing device using a drive mechanism associated with a computerreadable storing the computer executable components such as a CD-ROM,DVD-ROM, or network interface. Further, the component and/or data can beincluded in a single device or distributed in any manner. Accordingly,general purpose computing devices may be configured to implement theprocesses, algorithms and methodology of the present disclosure with theprocessing and/or execution of the various data and/or componentsdescribed above.

It should be emphasized that many variations and modifications may bemade to the above-described embodiments, the elements of which are to beunderstood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.

What is claimed is:
 1. A computer-implemented method comprising:receiving, at a cache component, an object for storage; segmenting theobject into a first fragment for storage in memory, a second fragmentfor storage in a first media having higher latency than the memory, anda third fragment for storage in a second media having higher latencythan the first media, wherein the size of the first fragment is based ona latency associated with retrieval of the second fragment, and whereinthe size of the second fragment is based on a latency associated withretrieval of the third fragment; receiving a request for the object at acache component; causing transmission of the first fragment from thememory; causing transmission of the second fragment without retainingthe second fragment in memory for subsequent processing; and causingtransmission of the third fragment without retaining the third fragmentin the memory for subsequent processing.
 2. A computer-implementedmethod comprising: receiving a request for an object at a cachecomponent; causing transmission of a first fragment of the object frommemory; causing transmission of a second fragment of the object withoutretaining the second fragment in memory for subsequent processing; andcausing transmission of a third fragment of the object without retainingthe third fragment in memory for subsequent processing.
 3. Thecomputer-implemented method of claim 2 further comprising retrieving thesecond fragment from local disk memory of the cache component.
 4. Thecomputer-implemented method of claim 2 further comprising retrieving thethird fragment from disk memory of another cache component.
 5. Thecomputer-implemented method of claim 2 further comprising retrieving thethird fragment from network-based memory.
 6. The computer-implementedmethod of claim 2 further comprising retrieving the third fragment froman origin server.
 7. The computer-implemented method of claim 2 furthercomprising collecting performance data associated with at least one ofthe retrieval of the second fragment or the transmission of the firstfragment.
 8. The computer-implemented method of claim 7 furthercomprising updating the size of the first fragment based on thecollected performance data.
 9. The computer-implemented method of claim8, wherein updating the size of the first fragment comprises storing anincremental fragment in the memory to supplement the first fragment. 10.The computer-implemented method of claim 2 further comprising updatingthe size of the first fragment based on a determination of a latencyassociated with retrieval of the third fragment.
 11. Thecomputer-implemented method of claim 2 further comprising updating thesize of the first fragment based on a frequency of a request for theobject, such that a change in the size of the first fragment is based ona change in request frequency.
 12. The computer-implemented method ofclaim 2 further comprising updating the size of the first fragment basedon a frequency of a request for another object related to the requestedobject, such that a change in the size of the first fragment is based ona change in request frequency for the related object.
 13. Thecomputer-implemented method of claim 2 further comprising: determining anew file size for the first fragment; and storing an incrementalfragment in the memory, wherein the first fragment and the incrementfragment correspond to the new file size.
 14. A system comprising: amemory for storing first fragments of objects; and one or more computingdevices configured with specific executable instructions and operativeto: receive a request for an object; cause transmission of a firstfragment of the object from the memory; cause transmission of a secondfragment of the object without retaining the second fragment in memoryfor subsequent processing; and cause transmission of a third fragment ofthe object without retaining the third fragment in memory for subsequentprocessing.
 15. The system of claim 14, wherein the one or morecomputing devices is further operative to retrieve the second fragmentfrom local disk memory of the one or more computing devices.
 16. Thesystem of claim 14, wherein the one or more computing devices is furtheroperative to retrieve the third fragment from disk memory of a differentcomputing device or cache component.
 17. The system of claim 14, whereinthe one or more computing devices is further operative to retrieve thethird fragment from network-based memory.
 18. The system of claim 14,wherein the one or more computing devices configured is furtheroperative to retrieve the third fragment from an origin server.
 19. Thesystem of claim 14, wherein the one or more computing devices is furtheroperative to collect performance data associated with at least one ofthe retrieval of the second fragment or the transmission of the firstfragment.
 20. The system of claim 19, wherein the one or more computingdevices is further operative to update the size of the first fragmentbased on the collected performance data.
 21. The system of claim 20,wherein updating the size of the first fragment comprises storing anincremental fragment in the memory to supplement the first fragment. 22.The system of claim 14, wherein the one or more computing devices isfurther operative to update the size of the first fragment based on adetermination of a latency associated with retrieval of the thirdfragment.
 23. The system of claim 14, wherein the one or more computingdevices is further operative to update the size of the first fragmentbased on a frequency of a request for the object, such that a change inthe size of the first fragment is based on a change in requestfrequency.
 24. The system of claim 14, wherein the one or more computingdevices is further operative to update the size of the first fragmentbased on a frequency of a request for another object related to therequested object, such that a change in the size of the first fragmentis based on a change in request frequency for the related object. 25.The system of claim 14, wherein the one or more computing devices isfurther operative to: determine a new file size for the first fragment;and store an incremental fragment in the memory, wherein the firstfragment and the increment fragment correspond to the new file size.